<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <!-- <style>
    .parent {
      height: 500px;
      width: 500px;
      border: 1px solid #666;
      /* line-height: 55px; */
      /* text-align: center; */

      /* display: flex;
      justify-content: center;
      align-items: center; */

      position: relative;
    }
    .children2 {
      width: 200px;
      height: 200px;
      border: 1px solid #999;
      position: absolute;

      /* 已知元素大小 */
      top: 50%;
      left: 50%;
      margin: -100px 0 0 -100px;

      /* 未知元素大小 */
      /* top: 50%;
      left: 50%;
      transform: translate(-50%, -50%); */


      /* 未知元素大小 */
      /* top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      margin: auto; */
    }
  </style>
  <body>
    <div class="parent">
      <div class="children1">
            这是一条文字
        </div> 
      <div class="children2"></div>
    </div>
    <script></script>
  </body> -->

  <style>
    .up {
      width: 100px;
      height: 0px;
      border: 50px solid;
      border-left: 200px solid;
      border-right: 0px solid;

      /* border-left: 0px solid transparent;
      border-bottom: 0px solid transparent;
      border-top: 0px solid transparent; */
      border-color: #893615 #e76b56 #a72310 #0c1f22;
      /* border-top: 100px solid red;  */
    }
    .down {
      width: 0;
      height: 0;
      border: 100px solid transparent;
      border-bottom: 100px solid blue; /*蓝色*/
    }
    .left {
      width: 0;
      height: 0;
      border: 100px solid transparent;
      border-left: 100px solid pink; /*黑色*/
    }
    .right {
      width: 0;
      height: 0;
      border: 100px solid transparent;
      border-right: 100px solid pink; /*黄色*/
    }
  </style>
  <body>
    <div class="up"></div>
    <div class="down"></div>
    <div class="left"></div>
    <div class="right"></div>
  </body>
</html>
